<s>
Cyclic	B-Protocol
Delay	I-Protocol
Diversity	I-Protocol
(	O
CDD	O
)	O
is	O
a	O
diversity	B-Protocol
scheme	I-Protocol
used	O
in	O
OFDM-based	O
telecommunication	O
systems	O
,	O
transforming	O
spatial	O
diversity	O
into	O
frequency	O
diversity	O
and	O
thus	O
avoiding	O
intersymbol	O
interference	O
.	O
</s>
<s>
The	O
idea	O
of	O
CDD	O
for	O
OFDM	B-Protocol
had	O
previously	O
also	O
been	O
submitted	O
as	O
a	O
patent	O
application	O
in	O
September	O
2000	O
.	O
</s>
